Hydrohematite is brighter than anhydrous Hematite (left), and it's also a brighter color. Credit: Si Athena Chen, Penn State
According to geoscientists, a combination of an earlier-debunked 19th century identification of a water-carrying mineral and the fact these rocks are very common on Earth suggests that there is a significant water reservoir on Mars.
Peter J. Heaney from Penn State, professor of geosciences said, "One of my students' experiments was to crystalize Hematite." "She had an iron-poor compound so I searched Google Scholar to find two papers that were published in the 1840s by German mineralogists who used wet chemistry to propose iron-poor versions hematite which contained water."
Rudolf Hermann dubbed his mineral turgite in 1844 and August Breithaupt in 1847 his hydrohematite. Heaney claims that these papers were incorrectly declared by other mineralogists using the newly invented X-ray Diffraction technique in 1920. However, the new technique was too primitive for hydrohematite and hematite to be distinguished.
Si Athena Chen was Heaney's doctoral candidate in geosciences. She began by collecting old samples that had been labeled as water. Heaney and Chen obtained a small amount of Breithaupt’s original sample. This was a sample that was labeled as Turgite from Smithsonian Institution. They also found five other samples in Penn State’s Frederick Augustus Genth collection.
Chen proved that these minerals are indeed light in iron. He used a variety of instruments, including synchrotron X ray diffraction and infrared spectrum spectroscopy. This was a more sensitive and refined method than the one Chen used in the mid-century. The mineral's hydroxyl is water.
Hydrohematite water on Earth and Mars. Credit: Earth & Mineral Sciences, Penn State
Researchers recently published in Geology that hydrohematite was common in low-temperature iron oxide occurrences on Earth. They also suggested that it could inventory large amounts of water in seemingly arid planetary environments like Mars' surface.
Chen stated, "I was trying out what the natural conditions were to form iron oxides." "What temperatures and pH are required to crystallize these hydrous phase and how can I synthesize them?"
She discovered that hydrohematite can form sedimentary layers at lower temperatures than 300°F.
Heaney stated that Mars' surface is likely to have originated in a time when it was wetter, and iron oxides were precipitated from that water. But the existence of hydrohematite is still speculation.
Hematite was the source of the blueberries discovered in 2004 by NASA's Opportunity Rover. The newest Mars rovers have X-ray difffraction devices to identify Hematite. However, these devices are not sufficiently sophisticated to distinguish between hydrohematite or hematite.
August Breithaupt, German mineralogist, discovered a specimen of hydrohematite in 1843. It still bears its original label. Credit: Andreas Massanek (TU Bergakademie Freiberg, Germany).
Heaney stated that "on Earth, these spherical structures were hydrohematite."
The researchers note that anhydrous hematitelacking waterand hydrohematitecontaining waterare two different colors, with hydrohematite being redder or containing dark red streaks.
Chen's experiments showed that hydrohematite, a naturally occurring mineral, contained between 3.6% and 7.8% water weight. Goethite had about 10% water weight. The researchers believe that Mars could have a significant water reserve, based on the amount of hydrated Iron minerals.
Mars is known as the red planet due to its color. This color comes from iron compounds found in the Martian soil. Researchers believe that Mars once had hydrohematite, which is essential for all life on Earth.
Further Glauconitic-like Clay found on Mars suggests that the planet once experienced habitable conditions
More information: Si Athena Chen and colleagues, Superhydrous Hematite & Goethite - A potential water reservoir within the red dust on Mars?, Geology (2021). Information from the Journal: Geology Si. Athena Chen and colleagues, Superhydrous Hematite & Goethite. A potential water reservoir within the red dust of Mars? (2021). DOI: 10.130/G48929.1